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Mining the phytomicrobiome to understand how bacterial coinoculations enhance plant growth.

Maymon M, Martínez-Hidalgo P, Tran SS, Ice T, Craemer K, Anbarchian T, Sung T, Hwang LH, Chou M, Fujishige NA, Villella W, Ventosa J, Sikorski J, Sanders ER, Faull KF, Hirsch AM - Front Plant Sci (2015)

Bottom Line: In previous work, we showed that coinoculating Rhizobium leguminosarum bv. viciae 128C53 and Bacillus simplex 30N-5 onto Pisum sativum L. roots resulted in better nodulation and increased plant growth.The exact mechanisms whereby coinoculation results in increased plant growth are incompletely understood, but the synthesis of phytohormones and siderophores, the improved solubilization of inorganic nutrients, and the production of antimicrobial compounds are likely possibilities.Because B. simplex 30N-5 is not widely recognized as a Plant Growth Promoting Bacterial (PGPB) species, after sequencing its genome, we searched for genes proposed to promote plant growth, and then compared these sequences with those from several well studied PGPB species.

View Article: PubMed Central - PubMed

Affiliation: Departments of Molecular, Cell, and Developmental Biology, University of California, Los Angeles Los Angeles, CA, USA.

ABSTRACT
In previous work, we showed that coinoculating Rhizobium leguminosarum bv. viciae 128C53 and Bacillus simplex 30N-5 onto Pisum sativum L. roots resulted in better nodulation and increased plant growth. We now expand this research to include another alpha-rhizobial species as well as a beta-rhizobium, Burkholderia tuberum STM678. We first determined whether the rhizobia were compatible with B. simplex 30N-5 by cross-streaking experiments, and then Medicago truncatula and Melilotus alba were coinoculated with B. simplex 30N-5 and Sinorhizobium (Ensifer) meliloti to determine the effects on plant growth. Similarly, B. simplex 30N-5 and Bu. tuberum STM678 were coinoculated onto Macroptilium atropurpureum. The exact mechanisms whereby coinoculation results in increased plant growth are incompletely understood, but the synthesis of phytohormones and siderophores, the improved solubilization of inorganic nutrients, and the production of antimicrobial compounds are likely possibilities. Because B. simplex 30N-5 is not widely recognized as a Plant Growth Promoting Bacterial (PGPB) species, after sequencing its genome, we searched for genes proposed to promote plant growth, and then compared these sequences with those from several well studied PGPB species. In addition to genes involved in phytohormone synthesis, we detected genes important for the production of volatiles, polyamines, and antimicrobial peptides as well as genes for such plant growth-promoting traits as phosphate solubilization and siderophore production. Experimental evidence is presented to show that some of these traits, such as polyamine synthesis, are functional in B. simplex 30N-5, whereas others, e.g., auxin production, are not.

No MeSH data available.


Comparison of flagellar open reading frame (ORF) clusters. The top cluster is from B. simplex 30N-5, which consists of two unlinked regions. The bottom cluster is from B. cereus JM-Mgvxx-63 where most of the genes related to B. simplex are within a single region on the chromosome.
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Figure 4: Comparison of flagellar open reading frame (ORF) clusters. The top cluster is from B. simplex 30N-5, which consists of two unlinked regions. The bottom cluster is from B. cereus JM-Mgvxx-63 where most of the genes related to B. simplex are within a single region on the chromosome.

Mentions: In response to root exudates, many bacteria migrate toward root surfaces and colonize roots. In B. amyloliquefaciens subsp. plantarum FZB42 and other Bacillus species, a number of genes are expressed (Chen et al., 2007), including flagellar genes (De Weger et al., 1987; Croes et al., 1993). In the B. simplex genome, flagellar and chemotaxis genes are located in two apparently unlinked areas (Figure 4). A similar arrangement exists for other PGPB Bacillus strains, such as B. firmus DS1, B. kribbensis DSM 17871, B. megaterium DSM 319 (Supplementary Figure 2), and the two Paenibacillus species included in our analysis (data not shown). However, a major difference in arrangement was observed in B. cereus, which contains strains that can be either beneficial or pathogenic (Bottone, 2010). For example, five chemotaxis-associated genes (cheABCD and W) within the flagellar gene operon are conserved among B. simplex and related PGP strains (Figure 4, Supplementary Figure 3). However, the chemotaxis genes, cheB and cheD, were not detected within the flagellar gene region of B. cereus JM-Mgvxx-63, which differs in organization (Figure 4). In addition, the flagellar genes are not highly related. For example, the flhF genes of B. simplex 30N-5 and B. cereus JM-Mgvxx-63 are 36% identical, but only 24% DNA identity is observed when the two fliS genes were compared.


Mining the phytomicrobiome to understand how bacterial coinoculations enhance plant growth.

Maymon M, Martínez-Hidalgo P, Tran SS, Ice T, Craemer K, Anbarchian T, Sung T, Hwang LH, Chou M, Fujishige NA, Villella W, Ventosa J, Sikorski J, Sanders ER, Faull KF, Hirsch AM - Front Plant Sci (2015)

Comparison of flagellar open reading frame (ORF) clusters. The top cluster is from B. simplex 30N-5, which consists of two unlinked regions. The bottom cluster is from B. cereus JM-Mgvxx-63 where most of the genes related to B. simplex are within a single region on the chromosome.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585168&req=5

Figure 4: Comparison of flagellar open reading frame (ORF) clusters. The top cluster is from B. simplex 30N-5, which consists of two unlinked regions. The bottom cluster is from B. cereus JM-Mgvxx-63 where most of the genes related to B. simplex are within a single region on the chromosome.
Mentions: In response to root exudates, many bacteria migrate toward root surfaces and colonize roots. In B. amyloliquefaciens subsp. plantarum FZB42 and other Bacillus species, a number of genes are expressed (Chen et al., 2007), including flagellar genes (De Weger et al., 1987; Croes et al., 1993). In the B. simplex genome, flagellar and chemotaxis genes are located in two apparently unlinked areas (Figure 4). A similar arrangement exists for other PGPB Bacillus strains, such as B. firmus DS1, B. kribbensis DSM 17871, B. megaterium DSM 319 (Supplementary Figure 2), and the two Paenibacillus species included in our analysis (data not shown). However, a major difference in arrangement was observed in B. cereus, which contains strains that can be either beneficial or pathogenic (Bottone, 2010). For example, five chemotaxis-associated genes (cheABCD and W) within the flagellar gene operon are conserved among B. simplex and related PGP strains (Figure 4, Supplementary Figure 3). However, the chemotaxis genes, cheB and cheD, were not detected within the flagellar gene region of B. cereus JM-Mgvxx-63, which differs in organization (Figure 4). In addition, the flagellar genes are not highly related. For example, the flhF genes of B. simplex 30N-5 and B. cereus JM-Mgvxx-63 are 36% identical, but only 24% DNA identity is observed when the two fliS genes were compared.

Bottom Line: In previous work, we showed that coinoculating Rhizobium leguminosarum bv. viciae 128C53 and Bacillus simplex 30N-5 onto Pisum sativum L. roots resulted in better nodulation and increased plant growth.The exact mechanisms whereby coinoculation results in increased plant growth are incompletely understood, but the synthesis of phytohormones and siderophores, the improved solubilization of inorganic nutrients, and the production of antimicrobial compounds are likely possibilities.Because B. simplex 30N-5 is not widely recognized as a Plant Growth Promoting Bacterial (PGPB) species, after sequencing its genome, we searched for genes proposed to promote plant growth, and then compared these sequences with those from several well studied PGPB species.

View Article: PubMed Central - PubMed

Affiliation: Departments of Molecular, Cell, and Developmental Biology, University of California, Los Angeles Los Angeles, CA, USA.

ABSTRACT
In previous work, we showed that coinoculating Rhizobium leguminosarum bv. viciae 128C53 and Bacillus simplex 30N-5 onto Pisum sativum L. roots resulted in better nodulation and increased plant growth. We now expand this research to include another alpha-rhizobial species as well as a beta-rhizobium, Burkholderia tuberum STM678. We first determined whether the rhizobia were compatible with B. simplex 30N-5 by cross-streaking experiments, and then Medicago truncatula and Melilotus alba were coinoculated with B. simplex 30N-5 and Sinorhizobium (Ensifer) meliloti to determine the effects on plant growth. Similarly, B. simplex 30N-5 and Bu. tuberum STM678 were coinoculated onto Macroptilium atropurpureum. The exact mechanisms whereby coinoculation results in increased plant growth are incompletely understood, but the synthesis of phytohormones and siderophores, the improved solubilization of inorganic nutrients, and the production of antimicrobial compounds are likely possibilities. Because B. simplex 30N-5 is not widely recognized as a Plant Growth Promoting Bacterial (PGPB) species, after sequencing its genome, we searched for genes proposed to promote plant growth, and then compared these sequences with those from several well studied PGPB species. In addition to genes involved in phytohormone synthesis, we detected genes important for the production of volatiles, polyamines, and antimicrobial peptides as well as genes for such plant growth-promoting traits as phosphate solubilization and siderophore production. Experimental evidence is presented to show that some of these traits, such as polyamine synthesis, are functional in B. simplex 30N-5, whereas others, e.g., auxin production, are not.

No MeSH data available.